1. Field of the Invention
This invention relates to an electrical connector for connecting a flat-type conductor.
2. Description of the Related Art
The electrical connection between a flat-type conductor, such as a flat cable and a flexible board, and a terminal is generally performed by inserting part of the flat conductor carrying a contact section and also a movable member of the terminal into an electrical connector so that the contact section of the terminal is brought into resilient contact with the contact section of the conductor. In this case, the electrical connector is provided with a means for tentatively holding the flat conductor in the connector before inserting the movable member.
For example, as shown in FIG. 4, Japanese Patent Application Kokai Number 6-86289 discloses a connector having a plate-shaped terminal with a pair of arms extending in parallel to each other; an upper one is a holding arm and a lower one is a contact arm. When a flexible board is inserted between the two arms, a contact section of the flexible board is brought into contact with a contact projection of the contact arm and the two arms hold the flexible board to keep the contact between the contact section and contact projection.
Japanese Patent Application Kokai Number 8-180940 discloses that a locking claw integrally made with a housing engages, from the upper side of a flexible board (a printed circuit board), a cut-off portion provided at both edges of the flexible board to tentatively holding the flexible board. In addition, a movable member is inserted into the connector to prevent the warp of the locking claw thus preventing the drop off of the flexible board.
However, in Japanese Patent Application Number 6-86289, since the flexible board is held by the friction resistance, close work is required to increase the friction resistance upon insertion of the flexible board for firm hold. Also, it is difficult to confirm that the flexible board has been inserted up to the position for firm contact with the terminal. The friction resistance produced by the contact with the contact and holding arms is constant during the insertion of the flexible board and does not increase discontinuously at a specific position during the insertion. Accordingly, it is difficult to judge if the insertion has been stopped halfway.
In Japanese Patent Application Number 8-180940, it is easier to confirm that the flexible board has been inserted up to a predetermined position because the locking claw engages the cut-off portion of the flexible boars, which gives the feeling of click. However, the direction of the engagement between the locking claw and the cut-off portion and the direction of the contact between the flexible board and the contact projection are the same so that the depth of the engagement becomes small because of the warp of the flexible board by the contact pressure from the contact projection, which causes the problem that the locking claw is prone to come off. Also, when the flexible board is inserted into the housing with the guidance by guidance sides of the housing, if the width of the flexible board is larger than the distance of the guidance sides even only by little, the flexible board is warped by the guidance sides in the widthwise direction thereof, which causes insufficient engagement between the flexible board and locking claw.
Accordingly, it is an object of this invention to provide an electrical connector for connecting a flat conductor, wherein it is possible to confirm that the flat conductor has been inserted up to a predetermined position and firmly prevent the flat conductor from dropping off before the insertion of a movable member.
According to an aspect of the invention, an electrical connector for a flat conductor having a plurality of connection portions arranged on a face thereof in a widthwise direction thereof and at least one engagement step, comprises a housing, a plurality of terminals arranged in and supported by the housing and having contact portions, a movable member supported by the housing and pressing the flat conductor against the contact portions so that the contact portions are brought into resilient contact with the corresponding connection portions of the flat conductor when the movable member is moved to a closed position, and at least one engagement member provided on an opposite side of the contact portions with respect to the flat conductor and having engaging means for engaging the engagement step of the flat conductor in an insertion direction of the flat conductor in concert with the contact portions.
According to an aspect of the invention, since the flat conductor is held between the contact portions of the terminals and the engagement members, it is held firmly in the housing. Since the engagement between the engagement steps of the flat conductor and the engaging means of the engagement member provides the feeling of click, it can be confirmed by the user that the flat conductor has been inserted into the housing up to a predetermined position. In addition, the flat conductor is pressed by the contact portions to such a direction as the engagement is strengthen so that the flat conductor does not come off easily. The engagement between the engagement steps and the engaging means acts as tentative holding of the flat conductor before the movable member is rotated to the closed position. As a result, it is prevented that the flat conductor moves from a predetermined position before or during the movement of the flat conductor to the closed position.
When the movable member is rotated to the closed position during the tentative holding, although the depth of the engagement between the engaging means of the engagement member and the engagement steps of the flat conductor is decreased a little, the flat conductor is strongly held between the movable member and the contact portions of the terminals so that the large holding strength can be obtained. The tentative holding is sufficient if the flat conductor does not move from a predetermined position during the movement of the movable member to the closed position.
According to another aspect of the invention, the engagement member is flexible and the engaging means of the engagement members are provided outside a range of the contact portions of the terminals in a direction of arrangement of the terminals. Accordingly, the engagement members engage the engagement steps provided at sides of the flat conductor. Since the sides of the flat conductor is outside the range of the contact portions of the terminals, the size of the connector is minimized in the widthwise direction thereof.
It is preferable that positions of the engaging means and the contact portions are offset in an insertion direction of the flat conductor. With this structure, the amount of the displacement of the contact portions becomes large.
The engagement members may be made integrally with the housing. Alternatively, the engagement member may be made of a metal and supported by the housing, and includes a fixed portion exposed outside the housing for fixing the engagement member to a circuit board. The flexible engagement member may have engaging means at such a position as the engaging means are displaced.